Geovany Soto has a tear in the meniscus in his left knee and will or already has undergone arthroscopic knee surgery. He'll be out at least 3 weeks. Blake Lalli was called up to fill his spot on the roster. The Cubs entered the season having a great deal of depth behind the plate. Soto was to be the starting catcher while Steve Clevenger made the big league team as a back-up out of spring training. Welington Castillo later replaced the injured Clevenger and now Lalli is replacing Soto, but not as the starter. Clevenger says he'll be returning in about a week so we could assume that he'll either immediately replace Lalli or will do so after a short rehab assignment. Castillo will get an opportunity to show he deserves more playing time with Soto and Clevenger out.
Chris Volstad was optioned to AAA after clearing optional waivers today. Lalli replaced him on the roster, but with Soto heading to the DL the Cubs will have to call up someone to replace Volstad. Travis Wood is expected to be called up in time for Volstad's next scheduled start. If Wood fares OK in the rotation the job will presumably be his to keep with Volstad waiting in AAA.
Kerry Wood is going to retire sometime in the next few days. I wouldn't be surprised to see Jeff Beliveau called up to replace Wood. This would give the Cubs two lefties. It's also possible they make room for Manny Corpas.
UPDATE: Wood talks about his retirement below.